하수처리를 위한 간헐 방류식 장기폭기 공정에서 아질산염의 축적에 영향을 미치는 인자 = Factors affecting nitrite build - up in an intermittently decanted extended aeration process for wastewater treatment

다국어 초록 (Multilingual Abstract)

An intermittently-aerated, intermittently-decanted single-reactor process (KIDEA) process : KIST intermittently decanted extended aeration process) was applied for nitrogen removal from wastewater. Synthetic wastewater with chemical oxygen demand (COD): nitrogen (N) ratio of approximately 5.25: 1 was used. The average COD removal efficiency reached above 95%, and under optimal conditions nitrogen removal efficiency also reached above 90%. This process consisted of 72 minute aeration, 48 minute settling and 24 minute effluent decanting with continuous feeding of influent wastewater from the bottom of the reactor, and did not require a separate anoxic mixing phase. In the process, nitritation (1^st step of nitrification) was induced but nitritation (2^nd step of nitrification) was suppressed. Main factors responsible for the accumulation of nitrite ion in the experimental condition were free ammonium and dissolved oxygen. This condition of nitrite build-up accelerated by continuous feed flow in the bottom of the KIDEA reactor because of high concentration of ammonia nitrogen in the influent. This research provides one of answers to control nitrate build-up.